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This study explores determinants of firms’ economic, social and environmental upgrading and downgrading trajectories in South Africa, with a focus on the manufacturing sector. Specifically, it considers connections between firms’ buyer and supplier relationships and their upgrading outcomes. Data is drawn from the World Bank Enterprise Surveys of 2007 and 2020 and analysed using social network and econometric analysis.

This study explores determinants of firms’ economic, social and environmental upgrading and downgrading trajectories in South Africa, with a focus on the manufacturing sector. Specifically, it considers connections between firms’ buyer and supplier relationships and their upgrading outcomes. Data is drawn from the World Bank Enterprise Surveys of 2007 and 2020 and analysed using social network and econometric analysis.

Abstract In order to develop a deeper understanding of the behaviour of commercial automotive lithium-ion pouch cells under short-circuiting conditions, two scenarios were experimentally investigated and compared. Firstly, experiments were conducted by internally shorting 15 Ah cells by full nail penetration using three different nail materials; copper, steel and plastic. A second set of experiments involved externally shorting the cell tabs using an external circuit with a range of resistance values. In both scenarios the cell electrical and thermal response were determined by the shorting resistance. In the case of nail penetration there was a clear distinction between the outcome of the conducting and non-conducting nails, although the outcome using conducting nails suffered from poor reproducibility. The poor reproducibility was attributed to the variation in the contact resistance between the nail and the cell layers. Correlating the outcome of both tests can be used to estimate the shorting resistance and construct the current profile during nail penetration test.

Abstract In order to develop a deeper understanding of the behaviour of commercial automotive lithium-ion pouch cells under short-circuiting conditions, two scenarios were experimentally investigated and compared. Firstly, experiments were conducted by internally shorting 15 Ah cells by full nail penetration using three different nail materials; copper, steel and plastic. A second set of experiments involved externally shorting the cell tabs using an external circuit with a range of resistance values. In both scenarios the cell electrical and thermal response were determined by the shorting resistance. In the case of nail penetration there was a clear distinction between the outcome of the conducting and non-conducting nails, although the outcome using conducting nails suffered from poor reproducibility. The poor reproducibility was attributed to the variation in the contact resistance between the nail and the cell layers. Correlating the outcome of both tests can be used to estimate the shorting resistance and construct the current profile during nail penetration test.

This research evaluates data centers as an emergency source of virtual inertia and fast frequency response, using PMUs to detect disturbances. The performance of the proposed method is validated using DIgSILENT PowerFactory simulation, calibrated using a real frequency event that occurred in the Irish power system. Wind generation is significant in the Irish system and significantly higher levels are required to reach renewable energy targets. Wind power, like photovoltaics, are mediated by power electronics that do not inherently respond to frequency variation. This research addresses problems with the drop in system inertia and the availability of primary frequency response on systems with high non-synchronous infeed. Demand response has the potential to replace these services. Typically, a large number of domestic, or light industrial, loads are considered for such services, but these present challenges in terms of monitoring and control. This research focuses on the potential of large load data centers that incorporate uninterruptable power supplies as standard, therefore a demand response does not have a direct effect on operation.

This research evaluates data centers as an emergency source of virtual inertia and fast frequency response, using PMUs to detect disturbances. The performance of the proposed method is validated using DIgSILENT PowerFactory simulation, calibrated using a real frequency event that occurred in the Irish power system. Wind generation is significant in the Irish system and significantly higher levels are required to reach renewable energy targets. Wind power, like photovoltaics, are mediated by power electronics that do not inherently respond to frequency variation. This research addresses problems with the drop in system inertia and the availability of primary frequency response on systems with high non-synchronous infeed. Demand response has the potential to replace these services. Typically, a large number of domestic, or light industrial, loads are considered for such services, but these present challenges in terms of monitoring and control. This research focuses on the potential of large load data centers that incorporate uninterruptable power supplies as standard, therefore a demand response does not have a direct effect on operation.

Macropore formation on p‐type Si in the dark has been studied on 6‐inch wafers in aqueous HF solution. More than 109 pores with a diameter of 2.5 μm and a depth of 100 μm are obtained in a single etch step. These pores can be used as a template for the fabrication of high‐density MOS capacitors. If the current density is close to the characteristic peak for the anodic etching of Si in HF solutions, nanowires are obtained. The length of these wires can reach values up to 100 μm, while their width can be as small as 30 nm. This method is a suitable way to the high‐volume production of nanowires.